Tanning material and process of producing same



Patented Oct. 12, 1926.

UNITED STATES;

"PA ENT" ounce.

JOHN K. TULLIS, OF NEW. YORK NI mamrme MATERIAL ann'rnocnss or rnonuome sans.

No Drawing.

This invention relates to a tanning material or agent and a tanning process by which I am enabled to effect av satisfactory tanning ofhides by a single-bath process, This single-bath process, as herein described, may be followed, when desired, by a further final tanning operation in order to bring about certain results that may be desired in par.- ticular cases. i

.In practicing this invention I make use of various chrome compounds, together with certain sulfates or. a m xture of sulfates. I have found chromic and salts, such for example as the sodium bichromate or the bichromate of potassium, to be suitable,

although chromic acid itself may be used.

One or more of these chrome compounds are mixed with sulfates such as aluminum and magnesium for example, and I have found that this mixture gives a good tanning extract that may be used in a singlebath for tanning purposes, thus eliminating the necessity of first treating the hides in a bath to produce an initial or preliminary tanning and .then subsequently treating them in a different bath to' complete the tannin operation. In this way consider-- able la or is saved and the operation does not have to be watched as closely as is the case with a two-bath process.

The following is given as a specific example illustrating the invention. .It is not intended to restrict the invention to the particular details given in this example, as varlatlons of materials, proportions, etc.,

'can be made without departing from the spirit or scope of the invention.

I may prepare an aqueous solution containing about two parts .by weight of sodium bichromate, five parts of magnesium sulfate and four parts of aluminum sulfate. The

sodium bichromate may .be substituted.

'- wholly or in part by bichromate of potassium. The hide, after the usual beam-house preparation, is immersedin or wet with the liquid mixture of sulfates and .bichromate above referred to for a sufficiently long time for the tanning totake place. The time required will depend largely uponthe nature Application filed March 17, 1922. Serial No. 544,667.

and thickness of the hide to'be tanned, andthe concentration of the solution, and in general will vary from about three to six days. At the end of -this timethe hide'has further tanning bemg necessary.

.become well tanned so that the leather can be used for a variety of purposes without In case, however, it is desired to use the leather for sole leather or the like, I find it advisable-to subject the same to an additional tanning operation. For this final tanning'operation I may use well known tanning extracts, such as waste sulfite liquor;

or vegetable tanning materials, such as mangrove, oak,- hemlock, quebracho, or chestnut, etc.; or sulfite liquor mixed with these vegetable, tanning materials; or formalde-' 'hyde s'ulfonic acid or other synthetic tan- 7 ning' agents. The one-'bath tanning' operation of my invention does not interfere with the final tanning above mentioned when it is desired to use the latter for special purposes after the hide has been subjected-to the tanning operation with the the chrome com- 2. A composition to be used in a tanning process comprising sodium bichromate, magnesium'sulfate, and aluminum sulfate.

3. A composition to be used in a tanning process comprising sodium bichroma-te, mag-- nesium sulfate, and aluminum sulfate in the proportions of about 2 to 5- to 4 by weight.

4. The step inthe process of tanning hides which. comprises treating a hide with a mixture of a. chromic acid salt and magnesium and aluminum sulfates.

' 5. The step in the process of tanning hides which comprises treating a hide with 'an aqueous solution of a salt of chromic acid, magnesium sulfate and aluminum sulfate in substantially the. proportions of 2 to'-5 to 4 by weight.

In testimony whereof I aflix m si nature. I

OHN K." 

